Progressive increase in cell-mediated immunity against paternal transplantation antigens in parous mice after multiple pregnancies.

The development of cell-mediated immunity to paternally-derived foetal transplantation antigens in parous mice has been assessed by two techniques: skin grafting in an H-2 incompatible mating and a local graft-versus-host assay in an H-2 compatible mating. (1) Lymphoid cells from BALB/c females, parous one to seven times to C3H/Bi males, were injected i.p. into syngeneic males or females which were then grafted with skin from the paternal strain. A slightly accelerated rejection in the adoptively immunized recipients was observed. (2) Lymphoid cells from CBA females, parous one to five times to AKR males, were injected into the feet of young F hybrid recipients. The degree of popliteal lymph node enlargement was significantly greater in recipients of cells from parous than from virgin donors. Results using both techniques demonstrated that the development of cell-mediated immunity to paternal transplantation antigens is a regular feature in parous mice and that the degree of immunity increases with successive interstrain pregnancies.